Democratic presidential candidate Dick Gephardt (search) is picking up another union endorsement - his seventh.

The International Alliance of Theatrical Stage Employees and Moving Picture Technicians (search), or IATSE, will officially announce its support of the Missouri congressman on Tuesday in New York. The union has more than 100,000 members in the United States and Canada.

Union President Thomas C. Short said Monday that Gephardt "has demonstrated through words and most importantly his actions, that he supports working families. He has fought to protect the rights of unions to organize, bargain and represent their members."

The AFL-CIO's executive council will meet next week in Chicago to gauge the political temperature of its 65 affiliate unions and whether a single labor endorsement is even possible. An endorsement likely won't happen unless a candidate can receive the backing of unions representing two-thirds of all rank-and-file members.

Should the AFL-CIO (search) choose to enter the primary fray, Gephardt, a longtime ally of organized labor, is considered the most likely candidate to get an endorsement. The federation has granted only two early endorsements: Walter Mondale in 1984 and Al Gore in 2000.

Gephardt has made clear that he wants to join that list and fills his schedule with visits to union halls and meetings with labor leaders and their members.

So far, his support has come from mostly smaller unions. The largest is from the International Association of Machinists and Aerospace Workers (search), with 720,000 members.

Most of the large unions that spend a lot of money on elections have not chosen among the nine Democratic hopefuls. Some are waiting for the AFL-CIO to decide if it will endorse before acting.

Concern among labor leaders about whether Gephardt could beat President Bush next year and his disappointing showing in fund raising in the last quarter - $1 million less than his campaign had predicted - has emboldened some of his rivals to pursue union support.

Rival Joe Lieberman, the Connecticut senator, will speak to union leaders gathered in Florida on Tuesday for an organizing meeting.